source/lib/interface.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    multiple interface handling
   4    Copyright (C) Andrew Tridgell 1992-1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22
  23 static struct iface_struct *probed_ifaces;
  24 static int total_probed;
  25
  26 struct in_addr allones_ip;
  27 struct in_addr loopback_ip;
  28
  29 static struct interface *local_interfaces;
  30
  31 #define ALLONES  ((uint32)0xFFFFFFFF)
  32 #define MKBCADDR(_IP, _NM) ((_IP & _NM) | (_NM ^ ALLONES))
  33 #define MKNETADDR(_IP, _NM) (_IP & _NM)
  34
  35 /****************************************************************************
  36 Try and find an interface that matches an ip. If we cannot, return NULL
  37   **************************************************************************/
  38 static struct interface *iface_find(struct in_addr ip, BOOL CheckMask)
  39 {
  40         struct interface *i;
  41         if (is_zero_ip(ip)) return local_interfaces;
  42
  43         for (i=local_interfaces;i;i=i->next)
  44                 if (CheckMask) {
  45                         if (same_net(i->ip,ip,i->nmask)) return i;
  46                 } else if ((i->ip).s_addr == ip.s_addr) return i;
  47
  48         return NULL;
  49 }
  50
  51
  52 /****************************************************************************
  53 add an interface to the linked list of interfaces
  54 ****************************************************************************/
  55 static void add_interface(struct in_addr ip, struct in_addr nmask)
  56 {
  57         struct interface *iface;
  58         if (iface_find(ip, False)) {
  59                 DEBUG(3,("not adding duplicate interface %s\n",inet_ntoa(ip)));
  60                 return;
  61         }
  62
  63 #if !defined(__s390__)
  64         if (ip_equal(nmask, allones_ip)) {
  65                 DEBUG(3,("not adding non-broadcast interface %s\n",inet_ntoa(ip)));
  66                 return;
  67         }
  68 #endif
  69
  70         iface = SMB_MALLOC_P(struct interface);
  71         if (!iface) return;
  72
  73         ZERO_STRUCTPN(iface);
  74
  75         iface->ip = ip;
  76         iface->nmask = nmask;
  77         iface->bcast.s_addr = MKBCADDR(iface->ip.s_addr, iface->nmask.s_addr);
  78
  79         DLIST_ADD(local_interfaces, iface);
  80
  81         DEBUG(2,("added interface ip=%s ",inet_ntoa(iface->ip)));
  82         DEBUG(2,("bcast=%s ",inet_ntoa(iface->bcast)));
  83         DEBUG(2,("nmask=%s\n",inet_ntoa(iface->nmask)));
  84 }
  85
  86
  87
  88 /****************************************************************************
  89 interpret a single element from a interfaces= config line
  90
  91 This handles the following different forms:
  92
  93 1) wildcard interface name
  94 2) DNS name
  95 3) IP/masklen
  96 4) ip/mask
  97 5) bcast/mask
  98 ****************************************************************************/
  99 static void interpret_interface(char *token)
 100 {
 101         struct in_addr ip, nmask;
 102         char *p;
 103         int i, added=0;
 104
 105         zero_ip(&ip);
 106         zero_ip(&nmask);
 107
 108         /* first check if it is an interface name */
 109         for (i=0;i<total_probed;i++) {
 110                 if (gen_fnmatch(token, probed_ifaces[i].name) == 0) {
 111                         add_interface(probed_ifaces[i].ip,
 112                                       probed_ifaces[i].netmask);
 113                         added = 1;
 114                 }
 115         }
 116         if (added) return;
 117
 118         /* maybe it is a DNS name */
 119         p = strchr_m(token,'/');
 120         if (!p) {
 121                 ip = *interpret_addr2(token);
 122                 for (i=0;i<total_probed;i++) {
 123                         if (ip.s_addr == probed_ifaces[i].ip.s_addr &&
 124                             !ip_equal(allones_ip, probed_ifaces[i].netmask)) {
 125                                 add_interface(probed_ifaces[i].ip,
 126                                               probed_ifaces[i].netmask);
 127                                 return;
 128                         }
 129                 }
 130                 DEBUG(2,("can't determine netmask for %s\n", token));
 131                 return;
 132         }
 133
 134         /* parse it into an IP address/netmasklength pair */
 135         *p = 0;
 136         ip = *interpret_addr2(token);
 137         *p++ = '/';
 138
 139         if (strlen(p) > 2) {
 140                 nmask = *interpret_addr2(p);
 141         } else {
 142                 nmask.s_addr = htonl(((ALLONES >> atoi(p)) ^ ALLONES));
 143         }
 144
 145         /* maybe the first component was a broadcast address */
 146         if (ip.s_addr == MKBCADDR(ip.s_addr, nmask.s_addr) ||
 147             ip.s_addr == MKNETADDR(ip.s_addr, nmask.s_addr)) {
 148                 for (i=0;i<total_probed;i++) {
 149                         if (same_net(ip, probed_ifaces[i].ip, nmask)) {
 150                                 add_interface(probed_ifaces[i].ip, nmask);
 151                                 return;
 152                         }
 153                 }
 154                 DEBUG(2,("Can't determine ip for broadcast address %s\n", token));
 155                 return;
 156         }
 157
 158         add_interface(ip, nmask);
 159 }
 160
 161
 162 /****************************************************************************
 163 load the list of network interfaces
 164 ****************************************************************************/
 165 void load_interfaces(void)
 166 {
 167         const char **ptr;
 168         int i;
 169         struct iface_struct ifaces[MAX_INTERFACES];
 170
 171         ptr = lp_interfaces();
 172
 173         allones_ip = *interpret_addr2("255.255.255.255");
 174         loopback_ip = *interpret_addr2("127.0.0.1");
 175
 176         SAFE_FREE(probed_ifaces);
 177
 178         /* dump the current interfaces if any */
 179         while (local_interfaces) {
 180                 struct interface *iface = local_interfaces;
 181                 DLIST_REMOVE(local_interfaces, local_interfaces);
 182                 ZERO_STRUCTPN(iface);
 183                 SAFE_FREE(iface);
 184         }
 185
 186         /* probe the kernel for interfaces */
 187         total_probed = get_interfaces(ifaces, MAX_INTERFACES);
 188
 189         if (total_probed > 0) {
 190                 probed_ifaces = memdup(ifaces, sizeof(ifaces[0])*total_probed);
 191         }
 192
 193         /* if we don't have a interfaces line then use all broadcast capable
 194            interfaces except loopback */
 195         if (!ptr || !*ptr || !**ptr) {
 196                 if (total_probed <= 0) {
 197                         DEBUG(0,("ERROR: Could not determine network interfaces, you must use a interfaces config line\n"));
 198                         exit(1);
 199                 }
 200                 for (i=0;i<total_probed;i++) {
 201                         if (
 202 #if !defined(__s390__)
 203                             probed_ifaces[i].netmask.s_addr != allones_ip.s_addr &&
 204 #endif
 205                             probed_ifaces[i].ip.s_addr != loopback_ip.s_addr) {
 206                                 add_interface(probed_ifaces[i].ip,
 207                                               probed_ifaces[i].netmask);
 208                         }
 209                 }
 210                 return;
 211         }
 212
 213         if (ptr) {
 214                 while (*ptr) {
 215                         char *ptr_cpy = SMB_STRDUP(*ptr);
 216                         if (ptr_cpy) {
 217                                 interpret_interface(ptr_cpy);
 218                                 free(ptr_cpy);
 219                         }
 220                         ptr++;
 221                 }
 222         }
 223
 224         if (!local_interfaces) {
 225                 DEBUG(0,("WARNING: no network interfaces found\n"));
 226         }
 227 }
 228
 229
 230 /****************************************************************************
 231 return True if the list of probed interfaces has changed
 232 ****************************************************************************/
 233 BOOL interfaces_changed(void)
 234 {
 235         int n;
 236         struct iface_struct ifaces[MAX_INTERFACES];
 237
 238         n = get_interfaces(ifaces, MAX_INTERFACES);
 239
 240         if ((n > 0 )&& (n != total_probed ||
 241             memcmp(ifaces, probed_ifaces, sizeof(ifaces[0])*n))) {
 242                 return True;
 243         }
 244
 245         return False;
 246 }
 247
 248
 249 /****************************************************************************
 250   check if an IP is one of mine
 251   **************************************************************************/
 252 BOOL ismyip(struct in_addr ip)
 253 {
 254         struct interface *i;
 255         for (i=local_interfaces;i;i=i->next)
 256                 if (ip_equal(i->ip,ip)) return True;
 257         return False;
 258 }
 259
 260 /****************************************************************************
 261   check if a packet is from a local (known) net
 262   **************************************************************************/
 263 BOOL is_local_net(struct in_addr from)
 264 {
 265         struct interface *i;
 266         for (i=local_interfaces;i;i=i->next) {
 267                 if((from.s_addr & i->nmask.s_addr) ==
 268                    (i->ip.s_addr & i->nmask.s_addr))
 269                         return True;
 270         }
 271         return False;
 272 }
 273
 274 /****************************************************************************
 275   how many interfaces do we have
 276   **************************************************************************/
 277 int iface_count(void)
 278 {
 279         int ret = 0;
 280         struct interface *i;
 281
 282         for (i=local_interfaces;i;i=i->next)
 283                 ret++;
 284         return ret;
 285 }
 286
 287 /****************************************************************************
 288   return the Nth interface
 289   **************************************************************************/
 290 struct interface *get_interface(int n)
 291 {
 292         struct interface *i;
 293
 294         for (i=local_interfaces;i && n;i=i->next)
 295                 n--;
 296
 297         if (i) return i;
 298         return NULL;
 299 }
 300
 301 /****************************************************************************
 302   return IP of the Nth interface
 303   **************************************************************************/
 304 struct in_addr *iface_n_ip(int n)
 305 {
 306         struct interface *i;
 307
 308         for (i=local_interfaces;i && n;i=i->next)
 309                 n--;
 310
 311         if (i) return &i->ip;
 312         return NULL;
 313 }
 314
 315 /****************************************************************************
 316   return bcast of the Nth interface
 317   **************************************************************************/
 318 struct in_addr *iface_n_bcast(int n)
 319 {
 320         struct interface *i;
 321
 322         for (i=local_interfaces;i && n;i=i->next)
 323                 n--;
 324
 325         if (i) return &i->bcast;
 326         return NULL;
 327 }
 328
 329
 330 /* these 3 functions return the ip/bcast/nmask for the interface
 331    most appropriate for the given ip address. If they can't find
 332    an appropriate interface they return the requested field of the
 333    first known interface. */
 334
 335 struct in_addr *iface_ip(struct in_addr ip)
 336 {
 337         struct interface *i = iface_find(ip, True);
 338         return(i ? &i->ip : &local_interfaces->ip);
 339 }
 340
 341 /*
 342   return True if a IP is directly reachable on one of our interfaces
 343 */
 344 BOOL iface_local(struct in_addr ip)
 345 {
 346         return iface_find(ip, True) ? True : False;
 347 }